高性能电荷泵电路设计与HSPICE仿真

Design and HSPICE Simulation of High Performance Charge-Pump Circuit

电荷泵锁相环具有高速、低功耗、低抖动等特点。电荷泵是锁相环中的关键模块,它实质上是一个开关电流源,需具有精准稳定的恒流源和理想的开关。在模块运行中,一般会出现电荷共享及充放电电流不匹配等现象。通过自举的方法,可以较好地消除电荷共享现象;采用电流跟随电路,可以使充放电电流得到较好匹配。基于2.5 V0.25μm CMOS工艺,设计了一个高性能电荷泵。采用Synopsys公司的Hspice仿真软件,对设计的电路进行模拟仿真。结果显示,在1.45 V至2.0 V之间,充放电电流几乎相等。

Charge-pump phase-locked loops（CP-PLL） features high speed,low power,low jitter and so on.Charge-pump,a Key block in PLL,is essentially a switched current source,which requires a precise and stable constant current source and an ideal switch.However,charge sharing and charge/discharge mismatch would occur during operation.By bootstrapping,charge sharing could be eliminated,and by using a current follower circuit,the charge/discharge current could could be well matched.Based on 2.5 V 0.25 μm CMOS process,a high performance charge pump was designed and simulated with Hspice.Simulation results showed that charge and discharge currents of the circuit were almost equal in the voltage range from 1.45 V to 2.0 V.